V belt pulley



Sept 23, 1941 J. o. ALMEN 2,256,699

V BELT PULLEY Filed Nov. 13, 19259 Milli.. Humm!!! nnentor G ttomegs j Patented-Sept. 23, 19A

UNITED STATE vnr-:ur PULLEr John 0. Almen, Royal ak,

General Motors Corporation, corporation of Delaware Application vNovember 8 Claims.

The invention relates to expanding and contracting v belt pulleys of variable effective diameter, such as are used where speed ratio variation is required between a driving shaft and shaft driven bybelt therefrom. 'I

It 'relates especially to such V belt pulleys having one con'ed side movable relatively to another coaxially of the shaft on which they are mounted, to vary the effective diameter of the pulley for a V belt between said pulley sides, with spring means resiliently urging said sides towards each other to increase the effective diameter of the pulley. As usually constructed, one of the sides of the pulley is fixed to the shaft, and the other side slides on the-guides'or keyways on the shaft through which it drives or is driven, and when torque is being transmitted through the' pulley and its shaft there is considerable friction between the pulleyV and the guides or keyways, which interferes with axial movement of the pulley sides relatively to each other. c

The object ofthe invention. is a V belt pulley in which guides or keyways between the pulley and the shaft are eliminated.

Another object of the invention is a V belt .pulley in which the spring means itself serves as the driving connection between the adjustable parts of the pulley and the shaft.

Another object of the invention is a V belt pulley, in which the spring means is a disc spring provided with weights having a centrifugal force component tending to deflect the spring means, to vary the effective diameter of the pulley in accordance with the speed at which it is driven.

Another object of the invention is a V belt pulley in which all sliding bearings for the adjustable half of the pulley are eliminated.

A still further object of the invention is a variable ratio V belt pulley drive between two shafts in which the forces required to change the effective diameters of the pulleys are very small.

The above and other objects of the invention will' be apparent as the description proceeds.

According to the invention, radially corrugated disc springs at one and the same time serve` as spring means and as the driving connection between the adjustable half of the pulley and the shaft on which it is mounted. The radially corrugated disc springs may also serve as the sole means of supporting the adjustable half of the pulley on the shaft in a manner eliminating all sliding bearings. In' those cases where automatic adjustment in accordance with the speed is required, centrifugal weights are suitably dison the radially corrugated disc spring Mich., assigner to Detroit, Mich., a

13, 19:9. serial No. 303,990

(ci. 'x4-230.17)

Fig. 2 is an enlarged sectional view of part of Fig. 1.

Fig. 3 ls a .view of a V belt pulley in which the radially corrugated disc spring means serves also as the driving connection and the sole means of supporting the adjustable half of the pulleyon .its shaft.

Fig. 4 is an enlarged perspective view of one of the radially corrugated disc springs.

The V belt pulleys I and 2 of Figs. l and 2 are mounted on a shaft 3, which for purposes of illustration is shown provided with a clutch con- Fig. 1. The shaft 3 is driven by a pair of V belts 1 and 8, from theV belt pulleys Il and I2 on the driving shaft I2.

Each of the pulleys I and 2, has two coned sides il, I5, and It, I1, respectively. The side Il of the pulley 2 is secured to the shaft I against a shoulder I8 thereon by a key I8', and the side I5 of the pulley I is secured to the side I1 of the pulley 2 by a. number of bolts such as I9, which pass through tubular spacers such as 2l, extending through clearance holesv 2i in the side It of the pulley 2.

The sides Il and I6 of the pulleys I and 2 constitute the axially adjustable halves of the pulleys and are loose on the shaft 3. They are connected together by bolts such as 22 which pass through tubular spacers such as23, extending through clearance holes 24 in the side vI5 of the pulley I.

In compression between the side I4 of the pulley I and a nanged hub 25 secured to the end of the shaft 3 by a key 26 and a nut 21 'on the shaft 3, are a pair of radially corrugated disc springs 30 and 3l, of the conical or dished form shown most clearly in Fig. .4. They are arranged with their bases together and their apices spaced apart. the outer edges of the springs lll and 3| being interlocked by their corrugations as shown.

The inner edges of the springs 30 and Il engage lugs or teeth such as 32 and il arranged circumnection to the transmission of a motor vehicle, in

ferentially on the hub 25 and on the side I4 of the pulley I, respectively. These'lugs such as shoulder 56 threon and a bushing`51.

y clearance holes 54 in the side -and the side 46 of the pulley I2 32 and 33 are shaped to fit in theradially corrugated grooves on the outside surfaces of the springs 36 and 3| towards their apices. It will be appreciated that since the corrugations in the springs 38 and 3| are radial and divergent fromv the center outwards, both springs are automatically centered with the shaft 3 upon assembly, because the lugs such'as 32 and 33 will only t the corrugations in the sprlngsat a xed radial distance from the center thereof. It will also be seen that the spring means.3||, 3| yieldingly urges the sides I4 and |6'of the pulleys I and 2 towards the sides I6 andv I1 thereof, (i. e. towards a condition in which the pulleys have their `maximum .eective diameter) and at the saine'` time is the sole means of connecting the axially adjustable pulley sidesv |4 and I6 to the shaft 3,

for rotation therewith.

' The V beltpulleys II and I2 on thevshaft I3,l Y each'have two coned sides 44, 45, and 46, 41, re-

spectively. The side 44 of the pulley issecured to the shaft ls by a key 4s, and the side 4s of the pulley I2 is secured to the side 44 of the pulley by 'a number of bolts such as 49, which pass through tubular spacers such as.68, extending .through clearance holes 5| in the side 45 of the pulley The side 46 of the pulley I2 is itself held iixed axially of the shaft I3 between a The sides 45 and 41 of the pulleys II and I2 constitute 'the -axiallyadjustable halves of the pulleys, and are axially adjustable pulley sides 45 and 41 to the shaft "I3, for rotation-therewith.

As shown in Fig. 2,'weights such as 1Q and 1I are attached tothe disc springs 60 and 6I respectively in such a manner that a component of the centrifugal force of the weights tends to deflect the springs. 'I'he weights are hooked around the inner periphery of the springsand lie within they corrugations of the springs.

The relative speed ratio of the shafts |3 and 3 will change with the speed of the governed pulleys II and I2. It' will be appreciated that the ratio change characteristics can be varied by changing the relationship of the springs in the driving and driven pulleys, or by ,changing the number and size of the weights, or the location of their center of gravity, in relation to the point of attachment of the weights to the springs.

Referring now to Fig. 3, which shows a single y .V belt pulley suitable for a fan drive for instance,-

the pulley has two coned sides 88 and 8|.-of which the side 88 along with the fan 83 is secured to a hub 84 by bolts 85, the hub 84 being keyed to the shaft 86 by a key 81, and locked thereon by the nut 88 on the shaft 86. f

` The side 8| of the pulley, which is the adjustable half/of the pulley, is radially spaced away *from sliding,y contact on the shaft 86, and is resiliently supported concentrically of the shaft,

on two radially corrugated disc springs 90 and 9|. The inner edges of the springs 98 and 9| en gage lugs or teeth such as 92 and 93, arranged loose on the shaft I3. They are connected together by bolts such as 52, which pass through tubular spacers Isuch as 5.3, extending through 46 of the pulley I2. In compression between the fast side 46 of the pulley I2 and the loose side 45 of the pulley are a pair of radially ,corrugated Ldisc springs 60 and 6|, of the conical or dished form shown in Fig. 4. Unlike the disc springs 30 and 3| however, they are arranged with their apices towards 'each other and with their bases spaced apart, although, lin the position illustrated, in which the pulleys II and I2 have their maximum effective diameter, the outer edges of the springs are compressed together. w

'I'he outer edges of the springs 66 and,6|, engage lugs or teeth such as .62v and 63, arranged circumferentially on the side of the pulley II gether in slightly spaced relationship by a floating ring 65S The sides of the ring 65 are shaped to fit in the radially corrugated grooves facing each other in the springs 68 and 6I and the ring 4 is automatically centered relatively to thev two springs because it will only fit the radially corrugated grooves at a fixed distance from the center of the springs.

Both springs 68 and 6| are automaticallycentered with the shaft I3 upon assembly, because the lugs such as 62 and 63 will only fit the corrugations in the'v springs at a l xed radial distance from the center thereof.

It will beseen that the spring means 60, 6|

V yieldingly urges the sides 45 and 41 of the pulleys |I and I2 towards the sides 44 and 46 thereof,

` '(i. e. towards a condition in which the pulleys 1 have their maximum effective diameter) and at the same time is the sole means of connecting the lrespectively.

in axially spaced circles on a hub 94, which is secured to the shaft 86 against a shoulder' 95. The outer edges of the springs 90'and 8| engage lugs or teeth 96 and 91, arranged in axially spaced circles on the pulley side 8|.- The lugs'such as 92, 93 and 96, 91 areshaped to t corrugated grooves of the springs 90 and 9|. the lugs such as 92 and 93 fitting the outwardly divergent' grooves towards' the apices of the springs, urging-both springs in one direction, and the lugs suchas `96, 91-tting the outwardly divergent grooves 1towards their outer peripheries, Aurging both springs in an opposite direction.

The two springs 98 and 9| yieldingly urge the side 8| of the' pulley towards the side 80 thereof,

(i. e.'towards'a condition in which the pulley has the maximum effective diameter for the'V belt 98) and at the same time are the only means of supporting the axially movable side 8| of the pulley in axial alignment with the` fixed side 88, as well as being the sole means of connecting it to the shaft 86 for rotation therewith. It will be seen that all sliding bearings are dispensed.

with; v

A spring of the type shown in Fig. 4 has the' advantage of compactness and a rate which is controllable within wide limits without changing its overall dimensions.

(i. e. it may be a spring of which the deflecting force increases with deflection, of which no change of force is required for an increased deflection, or of which a lesser-force is required for an increased deflection).

If both the driving and the driven pulleys of a variable ratio V belt drive such as that shown in Figs. land 2, are each provided with zero rate spring means of equal force,;there would be a constant belt tension and'very little 'resistance to a change of ratio. If the pulley, or pulleys, onone shaft are provided with positive rate spring means, and those on the other shaft Vwith negative rate spring means, the springpressure fit in the radially It may have not only a positive rate, but a zero rate, or a negative rate,

-ratio.

spring' means will be increased as the effectiveA diameter of its pulleysis increased. The spring pressures in the pulleys on both shafts will be increased or decreased together, upon any change in ratio. It will be appreciated that as the spring pressure in the pulleys on both of the shafts is increased the belt tension will be increased, and vice versa. When the V belt pulleys provide a drive between a constant torque shaft to a variable torque shaft, the belt tension should be high when the eective pulley diameter on the constant torque shaft is small, and vice versa; the

use of a positive rate spring on the pulley of the constant torque shaft in conjunction with a negative rate spring on the pulley of the variable torque shaft will automatically give this change in belt tension.

`The force necessary to change the pulley diameters, is the difference between the, spring pressures in the driving and driven pulleys, and for this reason the springs should be matched so that the difference in spring pressure between them is small.

Actually, with positive and negative rate springs, there need be no difference between the.

two springfpressures at small, forces will be effective diameters of any drive ratio, and only required to change the I claim:

` 1. A shaft, an expanding and contracting V belt pulley thereon having one coned Aside movable relatively to another axiallybf the shaft, to vary the effective diameter ofthe pulleyl and radially corrugated disc spring means resiliently urging said movable side towards the other and tending to increase the effective diameter of the pulley; said radially corrugated disc spring lrneans being the sole-means of connecting the movable pulley side to therewith.

2. The combination according to claim 1, in which that pulley side which is connected to the shaft for rotation therewith, by radially corrugated disc spring means, the shaft, and the other of said sidessis secured to the shaft.

3. The combination according to claim 1. in

the shaft for rotationl which the 'disc spring means is provided with weights having a centrifugal force component .tending toV deflect the spring means, to vary the .effective diameter of the pulley in accordance with the speed at which it is driven. A

4. The combination according to claim l, in which the movable side of the pulley is radially spaced awa-y from sliding contact on the shaft and is resiliently supported concentrically of the shaft, on two radially corrugated axially spaced f disc springs, of which 'the inner edges engage the pulleys and the drive v is slidable axially on lugs on the shaft and the outer edges engage lugs on the said movable side of the pulley. u

l5. The combination according to claim 1, in which the radially corrugated disc spring means is a pair of 'conical radially corrugated disc springs with their bases interlocked and their apices spaced apart, the said apices respectively engaging, lugs on a hub secured to the shaft, and lugs on the movable pulley side.

6. A variable ratio V belt pulley drive between two shafts, 'each of said shafts having an expanding having one coned side movable relatively to another axially of the shaft, to vary the effective diameter ofthe pulley,. and disc spring means resiliently urging said movable side towards the other and tending to increase the effective diam- Aeter of the pulley; the disc spring means of one eter of the pulley, and disc spring means resiliently urging saidmovable side towards the other and tending to increase the effective diameter of the pulley; the disc spring means of-the pulley on the constant torque shaft having-r a positive of the pulley on rate, and the disc spring means the variable torqueshaft havingy a negative rate.

8.`The combination according to claim l-,in which, the radially corrugated disc spring means is the sole means of supporting the movable pulley side concentric with the shaftand in axial alignment with the other pulley' side.

AJOHN O. ALMEN.

and contracting V belt pulley thereon, 

